tìm x biết x(2x-4)=0

`x(2x-4)=0`

`⇔` \(\left[ \begin{array}{l}x=0\\2x-4=0\end{array} \right.\) 

`⇔` \(\left[ \begin{array}{l}x=0\\2x=4\end{array} \right.\) 

`⇔` \(\left[ \begin{array}{l}x=0\\x=2\end{array} \right.\) 

Vậy `x ∈ {0; 2}`